In communication networks, there is always a challenge to obtain good performance and capacity for a given communications protocol, its parameters and the physical environment in which the communication network is deployed.
In order for a wireless device to communicate in the communication network a communications session is established between the wireless device and a network node of the communication network. The wireless device and the network node are operatively connected to a radio access network, which maintains the communication session between the wireless device and the network node. The communication session involves utilizing a data link protocol between the wireless device and the network node.
Typically the communication session is packet based. In a packet based network applications and services may be characterized by traffic classes, e.g. such as background, interactive, streaming, and conversational. Different resource allocations may be preferred for the different traffic classes. It may therefore be beneficial for a wireless device to initiate resource modifications.
However, a resource modification initiated by a wireless device may fail due to that a Policy and Charging Rules Function (PCRF) has insufficient information to assign proper Policy and Charging Control rule precedence (PCC rule precedence) to the corresponding PCC rule to be applied with respect to the resource that is to be modified due to the wireless device initiated resource modification. In general terms the resource that is to be modified is the wireless device connection to a packet data network (PDN). A resource modification may add/modify/delete capabilities of the PDN connection.
The wireless device forms its requests by manipulating Traffic Flow Template (TFT) filters. The TFT filters may e.g. be used for matching user plane packets, and Quality of service (QoS) parameters or similar, which e.g. may determine the kind of packet forwarding QoS Class Indicator (QCI) and bitrates or similar. The 3rd Generation Partnership Project (3GPP) notion of TFT filters is defined in 3GPP TS 23.060 V11.2.0, clause 15.3. For the purpose of differentiating the packet forwarding behaviour 3GPP employs the notion of bearers and QCI is used as a bearer parameter. The QCI defines the packet forwarding behaviour. All bearers, except one, must have at least one TFT filter associated.
FIG. 6 illustrates at reference numeral 30 a known set of TFTs, one of which is denoted by reference numeral 31. Each TFT is associated with a bearer. In FIG. 6 the bearer associated with TFT 31 is denoted by reference numeral 32. Each TFT is associated with one or more TFT filters. In FIG. 6 one of the TFT filters associated with TFT 31 is denoted by reference numeral 33. Each TFT filter has a precedence value. In FIG. 6 the precedence value of TFT filter 33 is 20.
FIG. 7 illustrates at reference numeral 40 a known set of PCC rules, one of which is denoted by reference numeral 41. Each PCC rule is associated with one or more service data flow (SDF) filters. In FIG. 7 the SDF filter associated with PCC rule 41 is denoted by reference numeral 42. Each PCC rule has a precedence value. The precedence value of PCC rule 41 in FIG. 7 is woo.
The binding of TFTs and PCC rules etc. may be described as follows:                every SDF filter has a corresponding TFT filter,        each TFT filter is associated with a bearer that offers the same QoS profile (QCI) or similar as defined for the PCC rule containing the corresponding SDF filter,        the TFT filters are sorted in their order of precedence and the SDF filters are sorted first in their PCC rule order of precedence and second in the same order as their corresponding TFT filters yield the same sequence.        
When determining what bearer is appropriate for transferring a user plane packet, a packet matching process takes the TFT filters in their order of precedence. For the first matching TFT filter, the packet is sent on the bearer associated with that TFT filter. Further, the TFT filter has a precedence value that determines in what order TFT filters are tried in the matching process.
3GPP specifies the Policy and Charging Control (PCC) rule. The PCC rule is provided from the PCRF. The PCC rule is based on TFT filter(s) requested by the wireless device to include: (a) the Service Data Flow template, which is a list of Service Data Flow (SDF) filters, (b) the PCC rule precedence, and (c) the SDF filter identity for each SDF filter. Each PCC rule includes SDF filters for user plane packet matching and has a PCC rule precedence value. The scope of the PCC rule precedence value is among the PCC rules for the wireless device's connection to the PDN. The SDF filter identity is generated for the SDF filter in response to wireless device requests only and is not generated for SDF filters generated on initiative of the network.
The network and the wireless device uses TFT filters with a precedence value as the representation for the order in which TFT filters are tried in the matching process to determine what bearer is to be used for an individual payload packet. The TFT filter precedence representation has the scope of the wireless device connection to the PDN, and is thus common for all the bearers in that connection. Each TFT filter is associated with a specific bearer.
The network entity that handles the network end of the relation to the wireless device may have PCC enabled, implementing a Policy and Charging Enforcement Function (PCEF) or Bearer Binding and Event Reporting Function (BBERF), using the PCRF for policy decisions. The PCRF enforces policy decisions at the PCEF/BBERF by using PCC/QoS rules.
However, when the wireless device requests to add a TFT filter the PCRF does not have any knowledge of what PCC rule precedence may be assigned to the PCC rule. The PCRF may even be unaware about any particular relation between the TFT filter precedence for the new TFT filter and the PCC rule precedence.
Hence, there is a need for an improved handling of additions and/or modifications to TFT filters in a network.